CN112318123A

CN112318123A - C mark festival special machine tool

Info

Publication number: CN112318123A
Application number: CN202011219906.4A
Authority: CN
Inventors: 姚文中; 兰联合; 车辉; 赵雅娥; 刘刚; 张本军; 陈国荣
Original assignee: Baoji Hanwei Machine Tool Co ltd
Current assignee: Baoji Hanwei Machine Tool Co ltd
Priority date: 2020-11-05
Filing date: 2020-11-05
Publication date: 2021-02-05

Abstract

The invention discloses a C-standard section special machine tool which is provided with a vertical system and a horizontal system for simultaneously processing workpieces. The clamp base is used for placing a workpiece, and the clamping mechanism is used for positioning and clamping the workpiece and has the function of keeping the straightness of the workpiece with a certain length when the workpiece is machined. Through different vertical systems and horizontal systems, different faces of a workpiece are simultaneously machined, machining modes such as face milling, boring and boring of the workpiece can be completed simultaneously through one-time clamping, and mutual interference cannot be caused, so that the problems of repeated clamping and repeated adjustment in the machining process of the workpiece are solved, the machining precision and the machining efficiency of the workpiece are greatly improved, and the machining device is particularly suitable for large-batch production requirements. The finished workpieces and the workpieces to be processed are grabbed in one stroke through the automatic feeding and discharging mechanism, the idle stroke of the grabbing mechanism is saved, and the waiting time of continuous processing of a machine tool is saved.

Description

C mark festival special machine tool

Technical Field

The invention relates to the technical field of machine tool machining, in particular to a machine tool special for a C standard section.

Background

The existing machine tools are separated in vertical and horizontal modes. A horizontal lathe is a machine tool for turning a rotating workpiece mainly with a lathe tool. Is the most widely used type of machine tool in machine manufacturing and repair factories. The milling machine is a machine tool for milling a workpiece by using a milling cutter. The vertical milling machine can mill planes, grooves, gear teeth, threads and spline shafts, can also process complex molded surfaces, has higher efficiency than a planer, and is widely applied to mechanical manufacturing and repairing departments. For complex workpieces, the workpieces need to be separately machined through a lathe and a milling machine, so that the clamping times of the workpieces are increased, the workpieces are adjusted and machined for multiple times, the whole machining process is time-consuming and labor-consuming, the machining efficiency is extremely low, the machining precision cannot be guaranteed, and the requirement for large-batch production cannot be met. On the basis of the problem, the lengthened workpiece needs to be clamped on a separate lathe or milling machine for multiple times, so that the accumulated machining error is further increased, and certain machining difficulty is caused for the workpiece with a certain length and complex machining.

Disclosure of Invention

Aiming at the existing problems, the invention aims to provide a special machine tool for C-standard joints, different surfaces of a workpiece are simultaneously machined through different vertical systems and horizontal systems, the machining modes of surface milling, boring and the like of the workpiece can be simultaneously completed through one-time clamping, and mutual interference cannot be caused, so that the problems of repeated clamping and repeated adjustment in the machining process of the workpiece are solved, the machining precision and the machining efficiency of the workpiece are greatly improved, and the special machine tool is particularly suitable for large-batch production requirements.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows: a C-mark section special machine tool is provided with a vertical system and a horizontal system which are used for simultaneously processing workpieces; vertical system is including setting up branch base, cross slip table and the stand that sets gradually up in base one side, one side is equipped with vertical gliding rotatory slip table in the stand is located the base, is equipped with the cutter clamping part of direction down on rotatory slip table, with be equipped with on the stand lateral wall of the adjacent one side of rotatory slip table and be used for the cutter clamping part tool changing, and be equipped with the tool magazine of a plurality of cutters, horizontal system architecture is similar with vertical system architecture, and its difference with vertical system architecture lies in: the cutter clamping part level of horizontal system sets up in rotatory slip table one side, and the direction is towards vertical system, wherein be equipped with the anchor clamps base of placing the work piece on the base between vertical system and the horizontal system, be equipped with the fixture who is used for work piece location centre gripping on the anchor clamps base, this fixture has the straightness accuracy effect of work piece when being processed that keeps certain length.

Preferably, the clamping mechanism comprises a left clamping device and a right clamping device which are arranged at two ends of the clamp base, a first auxiliary supporting device and a second auxiliary supporting device and a middle clamping device which transversely slides are arranged between the left clamping device and the right clamping device in a transverse and longitudinal sliding mode, a positioning device for a workpiece is further arranged on the clamp base, and adjusting supporting mechanisms aiming at the machining position of the tool are arranged on the first auxiliary supporting device and the second auxiliary supporting device.

Preferably, the first auxiliary supporting device and the second auxiliary supporting device are both provided with a lifting base, the adjusting and supporting mechanism comprises an annular concave groove formed in the top surface of the lifting base, at least two top blocks which horizontally and circularly rotate along the annular concave groove are nested in the annular concave groove, and the top surface of each top block exceeds the surface of the lifting base by a certain height and abuts against the bottom surface of the workpiece.

Preferably, an automatic feeding and discharging mechanism is arranged on one side of the special machine tool along the length direction of the base and comprises a support frame, a moving table which horizontally slides along the length direction of the support frame and towards the direction of the clamp base is arranged on the support frame, and a gripper mechanism which vertically ascends and descends and is used for simultaneously clamping a finished workpiece and a workpiece to be machined is arranged at the bottom of the moving table.

Preferably, the gripper mechanism comprises a rectangular frame which is perpendicular to the moving platform and is rotationally arranged at the bottom of the moving platform along a vertical plane, grippers which are arranged at intervals are symmetrically arranged on the rectangular frame and two side edges of the clamp base in the length direction, and a self-locking device is arranged on each gripper.

Preferably, the tongs comprise a plurality of tapered blocks arranged at intervals in the circumferential direction, the self-locking device comprises an elastic sliding locking mechanism arranged on the inner side of the bottom of the tapered block, the elastic sliding locking mechanism comprises a groove formed in the inner side of the bottom of the tapered block, a rectangular block and a spring are sequentially arranged in the groove from top to bottom, and the outer side face of the rectangular block exceeds the inner wall face of the tapered block and is attached to the surface of a workpiece.

Preferably, one end of the tool clamping part, which clamps the tool, is provided with a clamping hole, and a balance positioning device for accurately clamping the tool is arranged in the clamping hole.

Preferably, the balance positioning device is an annular spring plate group which is uniformly distributed in the clamping hole along the axial distance and is used for elastically balancing a cutter rod of the cutter.

The invention has the beneficial effects that:

1. through different vertical systems and horizontal systems, different faces of a workpiece are simultaneously machined, machining modes such as face milling, boring and boring of the workpiece can be completed simultaneously through one-time clamping, and mutual interference cannot be caused, so that the problems of repeated clamping and repeated adjustment in the machining process of the workpiece are solved, the machining precision and the machining efficiency of the workpiece are greatly improved, and the machining device is particularly suitable for large-batch production requirements.

2. The finished workpieces and the workpieces to be processed are grabbed in one stroke through the automatic feeding and discharging mechanism, the idle stroke of the grabbing mechanism is saved, and the waiting time of continuous processing of a machine tool is saved.

3. The clamping mechanism clamps the whole workpiece and supports a processing position in a targeted manner, so that the workpiece is prevented from being bent by external force of a cutter.

4. The annular spring plate group balances the deflection of the tool shank, so that the whole tool is coaxial with the clamping hole, and the clamping precision of the tool and the machining precision of a workpiece are improved.

Drawings

Fig. 1 is a front view of the machine tool of the present invention.

Fig. 2 is a right side view of the machine tool of the present invention.

Fig. 3 is a top view of the machine tool of the present invention.

Fig. 4 is a front view of the clamping mechanism of the machine tool of the invention.

Fig. 5 is a top view of the clamping mechanism of the machine tool of the present invention.

Fig. 6 is a top view of the first auxiliary supporting device and the second auxiliary supporting device according to the present invention.

Fig. 7 is a front view structural diagram of the automatic loading and unloading mechanism of the present invention.

FIG. 8 is a top view of the rectangular frame of the present invention.

Fig. 9 is a front view structural diagram of the gripper of the invention.

FIG. 10 is a view showing the balance state of the pair of annular spring plates of the present invention with respect to the cutter.

Detailed Description

In order to make those skilled in the art better understand the technical solution of the present invention, the following further describes the technical solution of the present invention with reference to the drawings and the embodiments.

Referring to fig. 1-10, the C-standard special machine tool has a vertical system (shown in fig. i) and a horizontal system (shown in fig. ii) for simultaneously machining a workpiece 100, and further includes a numerical control system 24, a hydraulic system 25, a cooling system 26, and a chip removal system 27. Vertical system is including setting up branch base 2, cross slip table 3 and the stand 4 that sets gradually up in base 1 one side, stand 4 is located base 1 one side and is equipped with vertical gliding rotatory slip table 5, is equipped with the cutter clamping part 6 that the direction is down on rotatory slip table 5, with be equipped with on the stand 4 lateral wall of the adjacent one side of rotatory slip table 5 and be used for the 6 tool changeings of cutter clamping part, and be equipped with the tool magazine 17 of a plurality of cutters 18. The sliding and rotating of the rotary sliding table 5 correspondingly completes the tool changing action with the tool magazine 17. Through the cross sliding table 3 on the sub-base 2, the upright post 4 is transversely and longitudinally moved, and the rotary sliding table 5 and the cutter clamping part 6 are arranged on the upright post, so that a cutter clamped on the cutter clamping part 6 is moved and positioned to a coordinate point of the workpiece 100 to be machined to carry out accurate machining. The first tool magazine 7 can complete the replacement of the tool held by the tool holding portion 6. The vertical system accomplishes a vertical machining of the workpiece 100.

The horizontal system structure is similar to the vertical system structure, and the difference between the horizontal system structure and the vertical system structure is that: the cutter clamping part 6 of the horizontal system is horizontally arranged on one side of the rotary sliding table 5 and faces towards the vertical system. The horizontal system completes the horizontal processing mode of the workpiece 100. Because the processing surfaces of the vertical system and the horizontal system are different and do not interfere with each other, the horizontal system and the vertical system which have two different processing directions and simultaneously process solve the problems of repeated clamping and repeated adjustment in the processing process of the workpiece 100, greatly improve the processing precision and the processing efficiency of the workpiece 100 and are particularly suitable for the large-batch production requirements.

In order to overcome the problem of bending of the workpiece 100 when the special machine tool is used for processing a long workpiece 100 and improve the processing and forming precision of the workpiece 100, a clamp base 7 for placing the workpiece 100 is arranged on the base 1 between the vertical system and the horizontal system, and a clamping mechanism for positioning and clamping the workpiece 100 is arranged on the clamp base 7 and has the function of keeping the straightness of the workpiece 100 with a certain length when being processed. The clamping mechanism clamps and fixes the workpiece 100, overcomes the problem that the workpiece 100 is easy to bend when being contacted by external force of a cutter, and improves the processing precision of the long workpiece 100.

Specifically, the clamping mechanism comprises a left clamping device 71 and a right clamping device 72 which are arranged at two ends of the clamp base 7, a first auxiliary supporting device 73 and a second auxiliary supporting device 75 and a middle clamping device 74 which slides transversely and longitudinally are arranged between the left clamping device and the right clamping device, the specific structure is as shown in fig. 4-5, a linear guide rail 19 is arranged on the clamp base 7 for the first auxiliary supporting device 73, the middle clamping device 74 and the second auxiliary supporting device 75 to slide transversely, and a sliding plate 20 is longitudinally arranged on the linear guide rail 19 for the first auxiliary supporting device 73 and the second auxiliary supporting device 75 to slide longitudinally. The fixture base 7 is further provided with a positioning device for positioning the workpiece 100, and the specific structure comprises side positioning reference devices symmetrically arranged on two sides of the fixture base 7 and an end positioning device arranged at one side end of the fixture base 7. The side edge positioning reference device is provided with an oil cylinder push rod 21 and a reference block 22 which are correspondingly arranged on the two sides of the clamp base 7 along the width, and the end part positioning device comprises an end part oil cylinder push rod 23.

During clamping, the workpiece 100 is placed between the oil cylinder push rod 21 and the datum block 22 of the side positioning datum device, the end part oil cylinder push rod 23 pushes the workpiece 100 to a set position, end face positioning of the workpiece 100 is completed, then the oil cylinder push rod 21 of the side positioning datum device longitudinally pushes the workpiece 100 to contact with the datum block to complete transverse positioning, after positioning is completed, the two ends of the workpiece 100 are clamped through the left clamping device 71 and the right clamping device 72, and then the middle position of the workpiece 100 is fixedly clamped and supported through the sliding middle clamping device 74. The clamping devices at the two end parts and the middle part are matched with the reference block 22 and clamped through the oil cylinder push rod 21. Finally, the first auxiliary supporting device 73 and the second auxiliary supporting device 75 are moved transversely and longitudinally through the specific processing position of the workpiece 100, and the two sides of the bottom of the processing position of the workpiece 100 are supported to overcome the external force action of the tool on the workpiece 100. The movable first auxiliary supporting device 73 and the second auxiliary supporting device 75 can be accurately adjusted according to the processing position of the horizontal plane, and can be more effectively attached to the processing position to support the workpiece 100. The supporting function of the side wall processing position of the workpiece 100 is completed by the sliding of the middle clamping device 74 and the cooperation of the left end clamping device 71 and the right end clamping device 72 on the two sides.

Since a horizontal surface of the workpiece 100 may have a need for precise machining at any coordinate position, in order to adapt to a complicated machining manner of the surface of the workpiece 100 and prevent the first auxiliary supporting device 73 and the second auxiliary supporting device 75 from interfering with the tool, each of the first auxiliary supporting device 73 and the second auxiliary supporting device 75 is provided with an adjusting supporting mechanism for a machining position of the tool 18. The adjusting and supporting mechanism can adjust the supporting point of the workpiece 100 in a small distance in a horizontal plane under the condition that the positions of the first auxiliary supporting device 73 and the second auxiliary supporting device 75 are not changed, and can avoid the interference problem to the cutter 18 under the condition of improving the supporting function of the workpiece 100.

Specifically, the first auxiliary supporting device 73 and the second auxiliary supporting device 75 are provided with a lifting base 8 so as to support according to the clamping height of the workpiece 100 or support the surface of the irregular workpiece 100 in a targeted manner. The adjusting and supporting mechanism comprises an annular concave groove 8a formed in the top surface of the lifting base 8, at least two jacking blocks 9 which horizontally rotate along the annular concave groove 8a in an annular manner are nested in the annular concave groove 8a, and the top surface of each jacking block 9 exceeds the surface of the lifting base 8 by a certain height and is abutted against the bottom surface of the workpiece 100. According to the change of the actual processing position, the adjusting top block 9 rotates in the annular concave groove 8a, has transverse and longitudinal position movement in the horizontal plane, can tightly attach to and avoid the processing position of a cutter to strongly support the workpiece 100, and effectively prevents the workpiece 100 from bending during processing.

In order to further improve the automation degree of the special machine tool, an automatic feeding and discharging mechanism is arranged on one side of the special machine tool along the length direction of the base 1 and comprises a support frame 10, a moving table 11 which horizontally slides along the length direction of the support frame 10 and towards the direction of the clamp base 7 is arranged on the support frame, and a gripper mechanism which vertically ascends and descends and is used for simultaneously clamping the finished workpiece 100 and the workpiece 100 to be machined is arranged at the bottom of the moving table 11. The gripper mechanism can grip the finished workpiece 100 and the workpiece 100 to be machined in one stroke, so that the idle stroke of the gripper mechanism is saved, and the waiting time of continuous machining of a machine tool is saved.

Specifically, the gripper mechanism comprises a rectangular frame 12 which is perpendicular to the moving platform 11 and is rotationally arranged at the bottom of the moving platform 11 along a vertical surface, and grippers 13 which are arranged at intervals are symmetrically arranged on the rectangular frame 12 and two side edges of the clamp base 7 in the length direction. Preferably, the automatic gripping of the gripper 13 is performed hydraulically or pneumatically. When grabbing, grabbing the workpiece 100 to be machined in the material storage area through the gripper on one side of the rectangular frame 12, moving the workpiece 100 to be machined to the position near the clamping mechanism through the transverse and longitudinal movement of the moving table 11, then moving the gripper 13 on the rectangular frame 12 on one side of the workpiece 100 to clamp the finished workpiece 100 on the clamping mechanism, then rotating the rectangular frame 12 to enable the finished workpiece 100 to be far away from the clamping mechanism, enabling the workpiece 100 to be machined to approach the clamping mechanism at the same time, and finally placing the workpiece 100 to be machined on the clamping mechanism for clamping to perform the next machining operation. The feeding and discharging mode can effectively avoid the empty travel of the gripper, and reduce the waiting time of continuous machining of the machine tool.

In order to avoid the problem that the workpiece 100 is inclined or falls off due to the fact that the gripping force is lost when the gripping arms are broken down, each gripping arm 13 is provided with a self-locking device. Specifically, tongs 13 comprises a plurality of tapered block 13a that the circumference interval was arranged, from locking device including the elastic sliding locking mechanism who sets up in tapered block 13a bottom inboard, this elastic sliding locking mechanism includes the recess 13b of seting up in tapered block 13a bottom inboard, from last rectangle piece 14 and the spring 15 of down being equipped with in proper order in the recess 13b, and the lateral surface of rectangle piece 14 surpasss tapered block 13a internal face, and laminate with work piece 100 surface. Firstly, the workpiece 100 is clamped by the gripper 13 by using external force, meanwhile, the rectangular block 14 is tightly attached to the side wall of the workpiece 100, when the workpiece 100 is clamped and lifted, the workpiece 100 moves downwards along with the gravity of the workpiece 100, the rectangular block 14 compresses a spring to move downwards through the friction force with the rectangular block 14, meanwhile, because the lower opening formed by the conical blocks 13a of the gripper 13 is smaller than the upper opening, the rectangular block 14 gradually converges towards the middle inside the gripper 13 when moving downwards, and then is pressed on the surface of the workpiece 100, the more the workpiece 100 moves downwards, the greater the clamping force of the rectangular block 14 is, and therefore, the self-locking effect on the workpiece 100 is realized. The problem that the workpiece 100 inclines or falls due to the fault of the gripper 13 is solved, the operation safety of the machine tool is improved, and meanwhile, the workpiece 100 can be prevented from falling and being damaged. In order to adapt to clamping operation of workpieces 100 with different specifications, the adhering surface of the rectangular block 14 and the workpiece 100 is preferably provided with a circular arc surface structure 14a, which can solve the problem that the rectangular block 14 cannot adhere to the surface of the workpiece 100 due to the change of the specification of the workpiece 100.

In the process of tool changing, a position error exists between the tool magazine 17 and the clamping hole 601, and a fit clearance exists between the tool and the clamping hole 601, so that clamping deviation exists between the machining tool 18 and the clamping hole 601 after tool changing is completed, and the machining precision of the machine tool is reduced. In order to solve the problem, the tool clamping portion 6 has a clamping hole 601 at one end for clamping the tool 18, and a balance positioning device for accurately clamping the tool 18 is arranged in the clamping hole 601, so that the error and the fit clearance can be balanced, the coaxiality of the tool 18 and the clamping hole 601 is improved, and the machining precision of the machine tool is further improved.

Specifically, the balance positioning device is an annular spring plate group 16 which is uniformly distributed in the clamping hole 601 along the axial direction at intervals and is used for elastically balancing a cutter rod 18a of the cutter 18. Each of the annular spring plate groups is constituted by spring plates 161 arranged at intervals in the circumferential direction (as shown in fig. 10). When the tool 18 is replaced, the arbor 18a of the tool 18 enters the clamping hole 601 and passes through the center of the annular spring plate group 16, the deflection of the arbor 18a is balanced by the elastic action of the plurality of spring plates 161 arranged in the circumferential direction, so that the whole tool 18 is coaxial with the clamping hole 601, and the spring plates 161 can facilitate the rapid clamping and taking out of the tool 18 without redundant limitation. In order to more quickly remove and replace the tool 18, it is preferable that one end of the spring piece 161 near the bottom side of the clamping hole 601 is formed into a circular arc surface to facilitate the tool 18 to be withdrawn, as shown in fig. 10A.

The principle of the invention is as follows: the finished workpiece 100 and the workpiece 100 to be processed are grabbed in one stroke through the automatic feeding and discharging mechanism, so that the idle stroke of the grabbing mechanism is saved, and the waiting time of continuous processing of a machine tool is saved. The workpiece 100 to be processed is placed on the clamping mechanism, the two ends of the workpiece are clamped and fixed at the left clamping device 71 and the right clamping device 72 respectively, and the middle position of the workpiece 100 is fixedly clamped and supported by sliding the middle clamping device 74. And finally, the first auxiliary supporting device 73 and the second auxiliary supporting device 75 are moved through the specific machining position of the workpiece 100, so that two sides of the machining position of the workpiece 100 are supported to overcome the external force action of the tool on the workpiece 100. The movable first auxiliary supporting device 73 and the second auxiliary supporting device 75 can be accurately adjusted according to the processing position of the horizontal plane, can be more effectively attached to the processing position to support the workpiece 100, and include that the top block 9 is adjusted to rotate in the annular concave groove 8a according to the change of the actual processing position, so that the workpiece 100 is strongly supported by being attached to and avoiding the processing position of the tool, and the workpiece 100 is effectively prevented from being bent during processing. The supporting function of the side wall processing position of the workpiece 100 is completed by the sliding of the middle clamping device 74 and the cooperation of the left end clamping device 71 and the right end clamping device 72 on the two sides. After clamping and fastening, processing is started, different surfaces of the workpiece 100 are simultaneously processed through different vertical systems and horizontal systems, and interference can not be caused, so that the problems of repeated clamping and repeated adjustment in the processing process of the workpiece 100 are solved, the processing precision and the processing efficiency of the workpiece 100 are greatly improved, and the method is particularly suitable for large-batch production requirements.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A C-mark section special machine tool is provided with a vertical system and a horizontal system which are used for simultaneously processing workpieces; vertical system is including setting up branch base (2), cross slip table (3) and stand (4) that set gradually up in base (1) one side, stand (4) are located base (1) one side and are equipped with vertical gliding rotatory slip table (5), are equipped with direction cutter clamping part (6) down on rotatory slip table (5), with be equipped with on the stand (4) lateral wall of the adjacent one side of rotatory slip table (5) and be used for cutter clamping part (6) tool changing, and be equipped with tool magazine (17) of a plurality of cutters (18), horizontal system architecture is similar with vertical system architecture, and its difference with vertical system architecture lies in: the horizontal system's cutter clamping part (6) level setting is in rotatory slip table (5) one side, and the direction is towards vertical system, wherein be equipped with anchor clamps base (7) of placing work piece (100) on base (1) between vertical system and the horizontal system, be equipped with the fixture who is used for work piece (100) location centre gripping on anchor clamps base (7), this fixture has the straightness accuracy effect of work piece (100) of keeping certain length when being processed.

2. The special machine tool for C standard joints according to claim 1, wherein: the clamping mechanism comprises a left end clamping device (71) and a right end clamping device (72) which are arranged at two ends of a clamp base (7), a first auxiliary supporting device (73), a second auxiliary supporting device (75) and a middle clamping device (74) which transversely slide are arranged between the left end clamping device and the right end clamping device in a transverse and longitudinal sliding mode, a positioning device used for positioning a workpiece is further arranged on the clamp base (7), and adjusting supporting mechanisms aiming at the machining position of the cutter (18) are arranged on the first auxiliary supporting device (73) and the second auxiliary supporting device (75).

3. The special machine tool for C standard joints according to claim 2, characterized in that: the first auxiliary supporting device (73) and the second auxiliary supporting device (75) are provided with lifting bases (8), the adjusting and supporting mechanism comprises an annular concave groove (8a) formed in the top surface of the lifting base (8), at least two jacking blocks (9) which horizontally rotate along the annular concave groove (8a) in an embedded mode are embedded in the annular concave groove (8a), and the top surface of each jacking block (9) exceeds the surface of each lifting base (8) by a certain height and is abutted to the bottom surface of the workpiece (100).

4. The special machine tool for C standard joints according to claim 3, wherein: the special machine tool is characterized in that an automatic feeding and discharging mechanism is arranged on one side of the special machine tool along the length direction of the base (1) and comprises a support frame (10), a moving table (11) which horizontally slides along the length direction of the support frame and towards the direction of the clamp base (7) is arranged on the support frame (10), and a gripper mechanism which vertically ascends and descends and is used for simultaneously clamping a finished workpiece and a workpiece to be machined is arranged at the bottom of the moving table (11).

5. The special machine tool for C standard joints according to claim 4, wherein: the gripper mechanism comprises a rectangular frame (12) which is perpendicular to the moving platform (11) and is rotationally arranged at the bottom of the moving platform (11) along a vertical surface, grippers (13) which are arranged at intervals are symmetrically arranged on the rectangular frame (12) and two side edges of the clamp base (7) in the length direction, and each gripper (13) is provided with a self-locking device.

6. The special machine tool for C standard joints according to claim 5, wherein: the gripper (13) comprises a plurality of conical blocks (13a) arranged at intervals in the circumferential direction, the self-locking device comprises an elastic sliding locking mechanism arranged on the inner side of the bottom of each conical block (13a), the elastic sliding locking mechanism comprises a groove (13b) formed in the inner side of the bottom of each conical block (13a), a rectangular block (14) and a spring (15) are sequentially arranged in the groove (13b) from top to bottom, and the outer side face of each rectangular block (14) exceeds the inner wall face of each conical block (13a) and is attached to the surface of a workpiece (100).

7. The special machine tool for C standard joints according to claim 6, wherein: one end of the tool clamping part (6) for clamping the tool (18) is provided with a clamping hole (601), and a balance positioning device for accurately clamping the tool (18) is arranged in the clamping hole (601).

8. The special machine tool for C standard joints according to claim 7, wherein: the balance positioning device is an annular spring leaf group (16) which is uniformly distributed in the clamping hole (601) along the axial distance and is used for elastically balancing a cutter rod (18a) of the cutter (18).